CJS

CJS Focus on Habitat Management and Conservation

Published: 18 August 2008

logo: NBN, National Biodiversity Network

In Association with: National Biodiversity Network Trust


logo: The River Restoration Centre - working to restore & enhance our riversRiver Restoration and Habitat Enhancement

 

RRC

The River Restoration Centre’s key role is to promote the concept of best practice management and river restoration.  It provides information and impartial advice based on the expertise of its staff and external advisors, an inventory of over 1500 projects collated by the Centre, and a UK-wide perspective based on knowledge gained over

the last 15 years.

 

Restoration and enhancement

River restoration and habitat enhancement is a means by which we can turn around the past trend of damage and degradation of our riverine ecosystems.  Many are no longer attractive or desirable places for the wildlife that they once supported.  Urban and rural rivers have  both been affected, by the dominant activities that were perceived to be the priority at the time.  By applying what fluvial-geomorphology tells us about the physical riverine system and what ecology tells us is needed for a diverse range of habitats and species, we can assess and respond to the need for conservation, enhancement or restoration of watercourses and floodplains.

 

The River Rhee

An upper reach of the River Cam, Cambridgeshire, the River Rhee is a good example of a degraded lowland agricultural river. A baseflow fed brook, once containing a healthy population of wild brown trout, it is now lost in its deepened channel and suffering

August 2001.  Reducing the bank height by 2m

August 2001.  Reducing the bank height by 2m (old dredgings) to create a shallow bank.  The small river is wide, slow flowing and silty.

 

August 2001.  Biodegradable coconut fibre rolls used

August 2001.  Biodegradable coconut fibre rolls used to narrow the channel and speed the flow to prevent silt settling over the gravel bed.

severe siltation problems.  An initial visit examined the opportunities for achieving floodplain restoration, and bringing visual and hydrological connectivity to the river. However, after critically assessing land, river and water levels it was concluded that floodplain restoration would not be possible in the main area proposed without having an impact on neighbouring farmers, and the adjacent road. This can often be a major limiting constraint.

June 2003.  Grasses and wildflowers colonising the bare re-profiled bank.

June 2003.  Grasses and wildflowers colonising the bare

re-profiled bank.  Typical marginal vegetation, having returned

to the river’s edge, helps to further narrow the channel and

provide cover for fish and invertebrates.

 

Due to the history of ‘improvement’ to land drainage (dredging the river deeper and frequent follow up work) there was also plenty of scope to enhance the bankside and in-river habitat.  Habitat enhancement works included channel narrowing to uncover the gravel bed, shallowing the profiling of banks and existing meanders to remove years of dredging material and nettle growth, and off-river backwater habitat creation as a refuge for fish and invertebrates in times of flood.  These were identified as options by carefully ‘reading the river’ and both aiding its natural recovery (which could take centuries in a lowland clay catchment) as well as removing obstacles to recovery (spoil embankments, steep slopes, etc). 

The works were funded by the Environment Agency and delivered by Roger Beecroft Wildlife and Countryside Services with support from RRC.

 

Benefits

Although a small scale scheme, this project has great potential as a demonstration site showing best practices for managing and rehabilitating previously heavily engineered rivers in flat, arable landscapes at low cost.  The landowner has a river he can now see without having to fight through nettles and peer over raised banks.  The silt has washed off of the gravel bed increasing fish and invertebrate habitat; the shallow marginal shelves support typical river’s edge plants and the stripped shallow banks are developing a more typical nutrient poor grass/wildflower cover.

 

Martin Janes, Managing Director. www.therrc.co.uk


Updated information February 2017

This case study features in RRC’s Fixed Point Photography Factsheet and Video. Find out more here: http://www.therrc.co.uk/supporting-uk-trusts-partnerships-and-community-groups-0

See more case studies at http://www.therrc.co.uk/case-studies 


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